Avoid use of NOTICE to wait for snapshot invalidation

This idea (implemented in commits and bc32a12e0db2 and 9e8fa05d3412) of
using notices to detect that a session is sleeping was unreliable, so
simplify the concurrency controller session to just look at
pg_stat_activity for a process sleeping on the injection point we want
it to hit.  This change allows us to remove a secondary injection point
and the alternative expected output files.

Reproduced by Alexander Lakhin following a report in buildfarm member
skink (which runs the server under valgrind).

Author: Mihail Nikalayeu <mihailnikalayeu@gmail.com>
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Discussion: https://postgr.es/m/3e302c96-cdd2-45ec-af84-03dbcdccde4a@gmail.com

0 files changed, 0 insertions, 0 deletions